Re: ROUGH IDLE
Hi Nick,<br />My Guess off the top of my head would be one of two things.If your outboard is NOT using oil injection and you are mixing the gas/oil,make sure your fuel to oil ratio is correct.Should be 50:1 ratio(1pt.oil to 6 gals gas)or(1 gal.oil to 50 gals. gas).Use a TCWIII(3) oil,not tcwII.An overrich mixture could be the cause.Use a premium 89 octane or higher gasoline(very important also).<br />Check with your manual or nearest dealer and make sure you have the correct spark plugs installed.Plug heat range is important on these motors.If your motor has no problem accelerating it most likely is NOT a carb problem.If you experience hesitation/stumbling on throttle UP than dirt in carbs may be it.I would suspect those plugs first.They may be surface-gap type(no electrode)and you may benefit from a slightly "hotter" plug.If NGK plugs,should be BU8S?(not sure)Maybe its just time to replace the plugs? I have a '86 Mercury 175 thats runs good but also loaded up when trolling.I'am told these motors run best off idle(better for speed than goin slow)and are prone to this annoyance.If you follow ALL my suggestions and change those old plugs you should have a all around better running motor.NOTE:Hesitation on acceleration could be carbs/fuel restriction/bad stator(see dealer)
P.S. Don't use automotive type carb/engine cleaners in your outboard as they are too harsh.Use marine cleaners...One last thought,Thermostats,are they installed?Are they working properly? When idling for a while,is the water stream comin out cold,luke warm or hot?Any motor has to reach its operating temperature to run efficently.If its staying too cool,it may run rough also.(I've heard of people removing the thermostats completely on these which is a NO! NO!).
